Lubricating oil compositions containing calcium acetate and lubricating solids



United States Patent 0 3,194,760 LUBRHIATING OIL COMPQQTIONS CONTAIN- ING CALCIUM ACETATE AND LUBRTCA'HNG SQLIDS Robert H. Davis, Woodbury, N.J., assignor to Socony Mobil Gil Qonrpany, Inc, a corporation of New York No Drawing. Filed Nov. 16, 1962, Ser. No. 238,269 8 Claims. (Cl. 252-25) This invention relates to novel extreme pressure lubricants. More specifically, it is directed to lubricating oil compositions, including greases, containing a combination of additives which synergistically enhance the extreme pressure characteristics of the lubricating oil.

It is well known that ordinary petroleum lubricating oils, of themselves, are incapable of withstanding the extremely high pressures encountered between the engaged metal surfaces in various types of modern machinery, such as the hypoid gears used in motor vehicles. As a solution to this problem, it has become the practice in the art to incorporate in the lubricating oil certain materials which under extreme pressure conditions form a lubricating film capable of withstanding these high pressures. These materials are known as extreme pressure or load-carrying agents. For example, it has been known for some time that layer lattice solids, such as molybdenum disulfide, stannic sulfide, graphite, mica, talc, soapstone, etc., possess lubricating properties and that they are highly effective extreme pressure agents for lubricating oil. These lubriacting solids have, therefore, been added to lubricating oils designed for heavy load application. More recently, calcium acetate has been recognized as having lubricating properties and that it is a highly effective extreme pressure agent for lubricating oil. However, the continued development of new types of machinery, such as smaller gear sets in automotive transmissions, requiring heavier unit loads has raised the extreme pressure requirements of lubricants. The provision of new and better extreme pressure lubricants is, therefore, of great importance to the lubricating art.

It has now been found, in accordance with this invention, that by incorporating in a lubricating oil, as extreme pressure additives, the combination of (a) a conventional layer lattice solid lubricant, such as molybdenum disulfide, stannic sulfide, graphite, mica, talc, soapstone or the like, and (b) calcium acetate, a synergistic increase in the extreme pressure properties of the oil over that provided by the incorporation of either one of these two types of additives alone is obtained. It is, therefore, the primary object of this invention to provide a new and highly improved class of extreme pressure lubricants, said lubricants containing as extreme pressure additives a layer lattice solid of the aforedescribed type and calcium acetate. Other and further objects of the invention will become apparent from the following detailed description thereof.

Because of their insolubility, the solid lubricants and the calcium acetate are incorporated in the oil as either gross suspensions or time dispersions. Particularly ad vantageous compositions are those comprising fine dispersions of the solids, including colloidal dispersions, containing a stabilizing agent to prevent the settling out of the additives in storage.

A full understanding of the invention will be had from the following illustrative examples and tests.

base oil in a Waring Blendor. The calcium acetate used was the hemi-hydrated form, i.e., Ca(C l-l O .%H O.

3,194,766 Patented July 13, 1965 ice The base oil used was a mixture composed of 40.5 weight percent 180 sec. (SUS) solvent-refined Cylinder Stock, 38.5 weight percent 200 sec. (SUS) solvent-refined Paraffinic Neutral Stock and 21.0 weight percent 155 sec. (SUS) solvent-refined Bright Stock.

Each of the above suspensions was tested (after thorough remixing just prior to the test) for its load-carrying ability in the well-known Shell 4-Ball Machine. Briefly, the test procedure is as follows. Three /2 inch SAE 52100 steel balls are clamped in a stationary ball cup. The lubricant under test is added to cover the balls. A fourth ball is held in a chuck at the lower end of a vertical spindle and is rotated at 1800 r.p.m. against the three stationary balls. A series of IO-second runs are made with increasing lever arm loads (increments of 10 kg.) until welding of the balls occurs. A new set of balls is installed between each run. The test results are summarized in Table I.

A second series of suspensions were prepared (Examples 9-11) in a similar fashion to those of the previous series, except that the calcium acetate used Was anhydrous calcium acetate. These oils were also subjected to the Shell 4-Ball Machine Test. These test results are shown in Table II.

A third series of oil suspensions were prepared (EX- amples l2l4) in the same manner as the initial series, except that the calcium acetate used was the mono-hydrated form, i.e., Ca(C H O .H O. THhese oils were also subjected to the 4-Ball Machine Test, with the results shown in Table III.

Table I Example Oa(C2HaO2).l/2H O, M08 Base oil, Shell 4-ball number wt. percent wt. perwt. per- Weld load,

cent cent kg.

Table II Example Ca(C H O2) M08 Base oil, Shell 4-ball number wt. percent wt. perwt. perweld load,

cent cent kg.

Table III Example 02(02H302)2.I'I20, MOS Base oil, Shell et-ball number wt. percent wt. perwt. perweld load,

cent cent kg.

The test results shown in Tables I, II and III clearly show a synergistic extreme pressure improving eflect between calcium acetate and molybdenum disulfide, the combination of the two in all cases providing a marked improvement overthat obtained with either one alone. Also, it is seen that the degree of hydration of the calcium acetate affects its performance in combination with the molybdenum disulfide. Thus, the anhydrous calcium acetate was the most effective while the hemi-hydrate was more eifective than the mono-hydrate. Also, it appears (Table I) that optimum performance is obtained by combining equal portions of the two additives.

A further series of oil suspensions were prepared (Examples -17) after the fashion of the first series, except that in this instance graphite was used in place of the molybdenum disulfide and the calcium acetate used was the hemi-hydrated form. These suspensions were also tested in the 4-Ball Machine with the results given in Table IV.

Still another series of oil suspensions were prepared (Examples 18-20) after the fashion of the first series, except that here the molybdenum disulfide was replaced by stannic sulfide and the calcium acetate used was the hemi-hydrated form. The results of the 4-Ball Machine Tests on these oils are given in Table V.

From the data in Tables IV and V, the synergistic extreme pressure effect provided by the combination of the calcium acetate with the graphite (Table IV) and with the stannic sulfide (Table V) is evident.

As stated previously, the principle of the present invention applies to greases as well as to liquid lubricating oil compositions. Also, as aforementioned, an advantageous form of the contemplated compositions is that provided by incorporating a stabilizing agent therein which will prevent separation of the solid materials from the oil during normal storage prior to use.

In a copending application of the present inventor, Serial No. 120,938, filed June 30, 1961, the stabilization of oil dispersions of calcium acetate by N-acyl-substituted sarcosine compounds of the formula:

wherein R represents an aliphatic, saturated or unsaturated, hydrocarbon radical containing from about 8 to about 24 carbon atoms, is disclosed. The stabilized calwhich gives it a desirable appearance and it need not be remixed prior to use.

The following example illustrates the useof a stabilized calcium acetate dispersion to form an extreme pressure grease in accordance with the instant invention.

EXAMPLE 21 (a) To 57 parts, by weight, of a solvent-refined naphthenic base oil, 500 sec. (SUS), there was added 40 parts, by weight, of calcium acetate (hemi-hydrated form) and 3 parts, by weight, of oleoyl sarcosine. The mixture was heated with stirring to 280 F. The resulting dispersion was then cooled to about 170 F. andpassed through a Manton-Gaulin Hcmogenizer operating at 3000 p.s.i. to provide a clear fluid dispersion.

, (b) A smooth grease was prepared by mixing parts, by weight, of the above dispersion (a) with 25 parts, by weight, of finely divided molybdenum disulfide in a grease kettle at 75 F. for three. hours...

When the aboye-prepared, grease was subjected to the Shell 4-Ball Machine test no welding occurred at 620 kgs, the maximum load capacity of the machine. The actual load-carrying ability of this grease is, therefore, greater than this latter value.

EXAMPLES 22 AND 23 Portions of the grease composition of Example 21 were diluted with base oil in amounts suflicient to form two fluid lubricants having total solids (i.e., calcium acetate and molybdenum disulfide) contents of 11% and 5%, by weight, respectively. These diluted compositions were also subjected to the Shell 4-B all Machine Test. Again, in each case no welding occurredatthe maximum load capacity of the test machine, i.e., 620 kgs.

While the invention has been illustrated herein by means of certain examples in which specific amounts of the calcium acetate and the lubricatingsolids were used, it will be appreciated that the principle of the invention applies to compositions containing varying amounts of the two additives. Thus, in actual practice where a lesser or greater degree of extreme pressure efiectiveness is required the amounts of the two additives can be correspondingly reduced or increased; or the proportions'of the two additives may be varied by reducing the amount of one and increasing the amount of the other. For example, for liquid lubricating oils suitable for automotive engines, transmissions, etc., only relatively small quantities of each additive, say, from about 0.1% to about 10%, need be used. On the other hand, for lubricant greases suitable foruse in metal processing as a drawing compound or in severe metal cutting operations, such as tapping or broaching, higheramounts u p to 60% or more, of the individual additives may be used, the total, however, generally not exceeding about Also, where a stabilizing agent, such as an N-acy1-substituted sacrosine compound, is employed, the amount may suitably range from about 0.01% to about 20%, by weight, ofv the composition depending upon the amount of calcium acetate and molybdenum disulfide in the composition, the usual amount being from about 0.1% to about 3%.

Besides the calcium acetate and layer lattice solid lubricants, the compositions of the invention may also contain other additives designed to impart other improvements therein, such as antioxidants, pour point depressants, viscosity index improvers, dispersants, rust inhibitors, antifoamants, etc. v 7

Having now fully described the invention, what is claimed as new and patentable is:

1. A lubricating composition comprising a-petroleum lubricating oil and based on the total composition (a) fromvabout 0.1% to about 60%, byweight, of calcium acetate and (b) from about 0.1% to about 60%, by weight, of a layer lattice solid lubricant, the total weight percentage of (a) and (b) in said composition being no greater than about 80.

2. A-composition according to claim 1 wherein the solid lubricant is molybdenum disulfide.

3. A composition according to claim 1 wherein the solid lubricant is stannic sulfide.

4. A composition according to claim 1 wherein the solid lubricant is graphite.

5.-.A lubricating composition comprising a petroleum oil having dispersed therein on the basis of the total composition (a) from about 0.1% -to about 60%, by weight, ofcalcium acetate, (b) from about 0.1% to about 60%, by weight, of a layer lattice solid lubricant and (c). from about 0.01% to about 20%, by weight, of an N-acylsubstituted sacrosine compound of the formula:

. Ha wherein R represents an aliphatic hydrocarbon radical of from about 8 to about 24 carbon atoms, the total weight percentage of (a) and (b) in said composition being no greater than about 80.

6. A composition according to claim wherein said layer lattice solid lubricant is molybdenum disulfide and said Nacyl-substituted sacrosine compound is oleoyl sarcosine.

7. A composition according to claim 5 wherein said layer lattice solid lubricant is stannic sulfide and said N- acyl-substituted sacrosine compound is oleoyl sacrosine.

8. A composition according to claim 5 wherein said layer lattice solid lubricant is graphite and said N-acylsubstituted sacrosine compound is oleoyl sacrosine.

References (Iited by the Examiner UNITED STATES PATENTS 2,421,543 6/47 Cook 252- 2,449,510 9/48- R 'obertson 25225 2,466,632 4/49 Larson 25225 2,635,078 4/53 Stross et al 25225 2,989,464 6/61 Panzer 25240.7 XR

FOREIGN PATENTS 829,000 2/60 Great Britain.

DANIEL E. WYMAN, Primary Examiner. 

1. A LUBRICATING COMPOSITION COMPRISING A PETROLEUM LUBRICATING OIL AND BASED ON THE TOTAL COMPOSITION (A) FROM ABOUT 0.1% TO ABOUT 60% BY WEIGHT, OF CALCIUM ACETATE AND (B) FROM ABOUT 0.1% TO ABOUT 60%, BY WEIGHT, OF A LAYER LATTICE SOLID LUBRICANT, THE TOTAL WEIGHT PERCENTAGE OF (A) AND (B) IN SAID COMPOSITION BEING NO GREATER THAN ABOUT
 80. 